hessian-lite/src/main/java/com/alibaba/com/caucho/hessian/io/JavaDeserializer.java - dubbo-hessian-lite - Git at Google

 /*
  * Copyright (c) 2001-2008 Caucho Technology, Inc.  All rights reserved.
  *
  * The Apache Software License, Version 1.1
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
  *    the documentation and/or other materials provided with the
  *    distribution.
  *
  * 3. The end-user documentation included with the redistribution, if
  *    any, must include the following acknowlegement:
  *       "This product includes software developed by the
  *        Caucho Technology (http://www.caucho.com/)."
  *    Alternately, this acknowlegement may appear in the software itself,
  *    if and wherever such third-party acknowlegements normally appear.
  *
  * 4. The names "Burlap", "Resin", and "Caucho" must not be used to
  *    endorse or promote products derived from this software without prior
  *    written permission. For written permission, please contact
  *    info@caucho.com.
  *
  * 5. Products derived from this software may not be called "Resin"
  *    nor may "Resin" appear in their names without prior written
  *    permission of Caucho Technology.
  *
  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED.  IN NO EVENT SHALL CAUCHO TECHNOLOGY OR ITS CONTRIBUTORS
  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
  * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * @author Scott Ferguson
  */

 package com.alibaba.com.caucho.hessian.io;

 import java.io.IOException;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.logging.Logger;

 /**
  * Serializing an object for known object types.
  */
 public class JavaDeserializer extends AbstractMapDeserializer {
     private static final Logger log
             = Logger.getLogger(JavaDeserializer.class.getName());

     private Class _type;
     private HashMap _fieldMap;
     private Method _readResolve;
     private Constructor _constructor;
     private Object[] _constructorArgs;

     public JavaDeserializer(Class cl) {
         _type = cl;
         _fieldMap = getFieldMap(cl);

         _readResolve = getReadResolve(cl);

         if (_readResolve != null) {
             _readResolve.setAccessible(true);
         }

         Constructor[] constructors = cl.getDeclaredConstructors();
         long bestCost = Long.MAX_VALUE;

         for (int i = 0; i < constructors.length; i++) {
             Class[] param = constructors[i].getParameterTypes();
             long cost = 0;

             for (int j = 0; j < param.length; j++) {
                 cost = 4 * cost;

                 if (Object.class.equals(param[j]))
                     cost += 1;
                 else if (String.class.equals(param[j]))
                     cost += 2;
                 else if (int.class.equals(param[j]))
                     cost += 3;
                 else if (long.class.equals(param[j]))
                     cost += 4;
                 else if (param[j].isPrimitive())
                     cost += 5;
                 else
                     cost += 6;
             }

             if (cost < 0 || cost > (1 << 48))
                 cost = 1 << 48;

             cost += (long) param.length << 48;

             if (cost < bestCost) {
                 _constructor = constructors[i];
                 bestCost = cost;
             }
         }

         if (_constructor != null) {
             _constructor.setAccessible(true);
             Class[] params = _constructor.getParameterTypes();
             _constructorArgs = new Object[params.length];
             for (int i = 0; i < params.length; i++) {
                 _constructorArgs[i] = getParamArg(params[i]);
             }
         }
     }

     /**
      * Creates a map of the classes fields.
      */
     protected static Object getParamArg(Class cl) {
         if (!cl.isPrimitive())
             return null;
         else if (boolean.class.equals(cl))
             return Boolean.FALSE;
         else if (byte.class.equals(cl))
             return new Byte((byte) 0);
         else if (short.class.equals(cl))
             return new Short((short) 0);
         else if (char.class.equals(cl))
             return new Character((char) 0);
         else if (int.class.equals(cl))
             return Integer.valueOf(0);
         else if (long.class.equals(cl))
             return Long.valueOf(0);
         else if (float.class.equals(cl))
             return Float.valueOf(0);
         else if (double.class.equals(cl))
             return Double.valueOf(0);
         else
             throw new UnsupportedOperationException();
     }

     static void logDeserializeError(Field field, Object obj, Object value,
                                     Throwable e)
             throws IOException {
         String fieldName = (field.getDeclaringClass().getName()
                 + "." + field.getName());

         if (e instanceof HessianFieldException)
             throw (HessianFieldException) e;
         else if (e instanceof IOException)
             throw new HessianFieldException(fieldName + ": " + e.getMessage(), e);

         if (value != null)
             throw new HessianFieldException(fieldName + ": " + value.getClass().getName() + " (" + value + ")"
                     + " cannot be assigned to '" + field.getType().getName() + "'", e);
         else
             throw new HessianFieldException(fieldName + ": " + field.getType().getName() + " cannot be assigned from null", e);
     }

     @Override
     public Class getType() {
         return _type;
     }

     @Override
     public Object readMap(AbstractHessianInput in)
             throws IOException {
         try {
             Object obj = instantiate();

             return readMap(in, obj);
         } catch (IOException e) {
             throw e;
         } catch (RuntimeException e) {
             throw e;
         } catch (Exception e) {
             throw new IOExceptionWrapper(_type.getName() + ":" + e.getMessage(), e);
         }
     }

     @Override
     public Object readObject(AbstractHessianInput in, String[] fieldNames)
             throws IOException {
         try {
             Object obj = instantiate();

             return readObject(in, obj, fieldNames);
         } catch (IOException e) {
             throw e;
         } catch (RuntimeException e) {
             throw e;
         } catch (Exception e) {
             throw new IOExceptionWrapper(_type.getName() + ":" + e.getMessage(), e);
         }
     }

     /**
      * Returns the readResolve method
      */
     protected Method getReadResolve(Class cl) {
         for (; cl != null; cl = cl.getSuperclass()) {
             Method[] methods = cl.getDeclaredMethods();

             for (int i = 0; i < methods.length; i++) {
                 Method method = methods[i];

                 if (method.getName().equals("readResolve") &&
                         method.getParameterTypes().length == 0)
                     return method;
             }
         }

         return null;
     }

     public Object readMap(AbstractHessianInput in, Object obj)
             throws IOException {
         try {
             int ref = in.addRef(obj);

             while (!in.isEnd()) {
                 Object key = in.readObject();

                 FieldDeserializer deser = (FieldDeserializer) _fieldMap.get(key);

                 if (deser != null)
                     deser.deserialize(in, obj);
                 else
                     in.readObject();
             }

             in.readMapEnd();

             Object resolve = resolve(obj);

             if (obj != resolve)
                 in.setRef(ref, resolve);

             return resolve;
         } catch (IOException e) {
             throw e;
         } catch (Exception e) {
             throw new IOExceptionWrapper(e);
         }
     }

     public Object readObject(AbstractHessianInput in,
                              Object obj,
                              String[] fieldNames)
             throws IOException {
         try {
             int ref = in.addRef(obj);

             for (int i = 0; i < fieldNames.length; i++) {
                 String name = fieldNames[i];

                 FieldDeserializer deser = (FieldDeserializer) _fieldMap.get(name);

                 if (deser != null)
                     deser.deserialize(in, obj);
                 else
                     in.readObject();
             }

             Object resolve = resolve(obj);

             if (obj != resolve)
                 in.setRef(ref, resolve);

             return resolve;
         } catch (IOException e) {
             throw e;
         } catch (Exception e) {
             throw new IOExceptionWrapper(obj.getClass().getName() + ":" + e, e);
         }
     }

     private Object resolve(Object obj)
             throws Exception {
         // if there's a readResolve method, call it
         try {
             if (_readResolve != null)
                 return _readResolve.invoke(obj, new Object[0]);
         } catch (InvocationTargetException e) {
             if (e.getTargetException() != null)
                 throw e;
         }

         return obj;
     }

     protected Object instantiate()
             throws Exception {
         try {
             if (_constructor != null)
                 return _constructor.newInstance(_constructorArgs);
             else
                 return _type.newInstance();
         } catch (Exception e) {
             throw new HessianProtocolException("'" + _type.getName() + "' could not be instantiated", e);
         }
     }

     /**
      * Creates a map of the classes fields.
      */
     protected HashMap getFieldMap(Class cl) {
         HashMap fieldMap = new HashMap();

         for (; cl != null; cl = cl.getSuperclass()) {
             Field[] fields = cl.getDeclaredFields();
             for (int i = 0; i < fields.length; i++) {
                 Field field = fields[i];

                 if (Modifier.isTransient(field.getModifiers())
                         || Modifier.isStatic(field.getModifiers()))
                     continue;
                 else if (fieldMap.get(field.getName()) != null)
                     continue;

                 // XXX: could parameterize the handler to only deal with public
                 try {
                     field.setAccessible(true);
                 } catch (Throwable e) {
                     e.printStackTrace();
                 }

                 Class type = field.getType();
                 FieldDeserializer deser;

                 if (String.class.equals(type))
                     deser = new StringFieldDeserializer(field);
                 else if (byte.class.equals(type)) {
                     deser = new ByteFieldDeserializer(field);
                 } else if (short.class.equals(type)) {
                     deser = new ShortFieldDeserializer(field);
                 } else if (int.class.equals(type)) {
                     deser = new IntFieldDeserializer(field);
                 } else if (long.class.equals(type)) {
                     deser = new LongFieldDeserializer(field);
                 } else if (float.class.equals(type)) {
                     deser = new FloatFieldDeserializer(field);
                 } else if (double.class.equals(type)) {
                     deser = new DoubleFieldDeserializer(field);
                 } else if (boolean.class.equals(type)) {
                     deser = new BooleanFieldDeserializer(field);
                 } else if (java.sql.Date.class.equals(type)) {
                     deser = new SqlDateFieldDeserializer(field);
                 } else if (java.sql.Timestamp.class.equals(type)) {
                     deser = new SqlTimestampFieldDeserializer(field);
                 } else if (java.sql.Time.class.equals(type)) {
                     deser = new SqlTimeFieldDeserializer(field);
                 }
                 // support generic type of map
                 else if (Map.class.equals(type)
                         && field.getGenericType() != field.getType()) {
                     deser = new ObjectMapFieldDeserializer(field);
                 } else if (List.class.equals(type)
                         && field.getGenericType() != field.getType()) {
                     deser = new ObjectListFieldDeserializer(field);
                 } else {
                     deser = new ObjectFieldDeserializer(field);
                 }

                 fieldMap.put(field.getName(), deser);
             }
         }

         return fieldMap;
     }

     abstract static class FieldDeserializer {
         abstract void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException;
     }

     static class ObjectFieldDeserializer extends FieldDeserializer {
         private final Field _field;

         ObjectFieldDeserializer(Field field) {
             _field = field;
         }

         @Override
         void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException {
             Object value = null;

             try {
                 value = in.readObject(_field.getType());

                 _field.set(obj, value);
             } catch (Exception e) {
                 logDeserializeError(_field, obj, value, e);
             }
         }
     }

     static class BooleanFieldDeserializer extends FieldDeserializer {
         private final Field _field;

         BooleanFieldDeserializer(Field field) {
             _field = field;
         }

         @Override
         void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException {
             boolean value = false;

             try {
                 value = in.readBoolean();

                 _field.setBoolean(obj, value);
             } catch (Exception e) {
                 logDeserializeError(_field, obj, value, e);
             }
         }
     }

     static class ByteFieldDeserializer extends FieldDeserializer {
         private final Field _field;

         ByteFieldDeserializer(Field field) {
             _field = field;
         }

         @Override
         void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException {
             int value = 0;

             try {
                 value = in.readInt();

                 _field.setByte(obj, (byte) value);
             } catch (Exception e) {
                 logDeserializeError(_field, obj, value, e);
             }
         }
     }

     static class ShortFieldDeserializer extends FieldDeserializer {
         private final Field _field;

         ShortFieldDeserializer(Field field) {
             _field = field;
         }

         @Override
         void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException {
             int value = 0;

             try {
                 value = in.readInt();

                 _field.setShort(obj, (short) value);
             } catch (Exception e) {
                 logDeserializeError(_field, obj, value, e);
             }
         }
     }

     static class ObjectMapFieldDeserializer extends FieldDeserializer {
         private final Field _field;

         ObjectMapFieldDeserializer(Field field) {
             _field = field;
         }

         @Override
         void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException {
             Object value = null;

             try {

                 Type[] types = ((ParameterizedType) _field.getGenericType()).getActualTypeArguments();
                 value = in.readObject(_field.getType(),
                         isPrimitive(types[0]) ? (Class<?>) types[0] : null,
                         isPrimitive(types[1]) ? (Class<?>) types[1] : null
                 );

                 _field.set(obj, value);
             } catch (Exception e) {
                 logDeserializeError(_field, obj, value, e);
             }
         }
     }

     static class ObjectListFieldDeserializer extends FieldDeserializer {
         private final Field _field;

         ObjectListFieldDeserializer(Field field) {
             _field = field;
         }

         @Override
         void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException {
             Object value = null;

             try {

                 Type[] types = ((ParameterizedType) _field.getGenericType()).getActualTypeArguments();
                 value = in.readObject(_field.getType(),
                         isPrimitive(types[0]) ? (Class<?>) types[0] : null
                 );

                 _field.set(obj, value);
             } catch (Exception e) {
                 logDeserializeError(_field, obj, value, e);
             }
         }
     }

     static class IntFieldDeserializer extends FieldDeserializer {
         private final Field _field;

         IntFieldDeserializer(Field field) {
             _field = field;
         }

         @Override
         void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException {
             int value = 0;

             try {
                 value = in.readInt();

                 _field.setInt(obj, value);
             } catch (Exception e) {
                 logDeserializeError(_field, obj, value, e);
             }
         }
     }

     static class LongFieldDeserializer extends FieldDeserializer {
         private final Field _field;

         LongFieldDeserializer(Field field) {
             _field = field;
         }

         @Override
         void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException {
             long value = 0;

             try {
                 value = in.readLong();

                 _field.setLong(obj, value);
             } catch (Exception e) {
                 logDeserializeError(_field, obj, value, e);
             }
         }
     }

     static class FloatFieldDeserializer extends FieldDeserializer {
         private final Field _field;

         FloatFieldDeserializer(Field field) {
             _field = field;
         }

         @Override
         void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException {
             double value = 0;

             try {
                 value = in.readDouble();

                 _field.setFloat(obj, (float) value);
             } catch (Exception e) {
                 logDeserializeError(_field, obj, value, e);
             }
         }
     }

     static class DoubleFieldDeserializer extends FieldDeserializer {
         private final Field _field;

         DoubleFieldDeserializer(Field field) {
             _field = field;
         }

         @Override
         void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException {
             double value = 0;

             try {
                 value = in.readDouble();

                 _field.setDouble(obj, value);
             } catch (Exception e) {
                 logDeserializeError(_field, obj, value, e);
             }
         }
     }

     static class StringFieldDeserializer extends FieldDeserializer {
         private final Field _field;

         StringFieldDeserializer(Field field) {
             _field = field;
         }

         @Override
         void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException {
             String value = null;

             try {
                 value = in.readString();

                 _field.set(obj, value);
             } catch (Exception e) {
                 logDeserializeError(_field, obj, value, e);
             }
         }
     }

     static class SqlDateFieldDeserializer extends FieldDeserializer {
         private final Field _field;

         SqlDateFieldDeserializer(Field field) {
             _field = field;
         }

         @Override
         void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException {
             java.sql.Date value = null;

             try {
                 java.util.Date date = (java.util.Date) in.readObject();
                 if (date != null)
                     value = new java.sql.Date(date.getTime());

                 _field.set(obj, value);
             } catch (Exception e) {
                 logDeserializeError(_field, obj, value, e);
             }
         }
     }

     static class SqlTimestampFieldDeserializer extends FieldDeserializer {
         private final Field _field;

         SqlTimestampFieldDeserializer(Field field) {
             _field = field;
         }

         @Override
         void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException {
             java.sql.Timestamp value = null;

             try {
                 java.util.Date date = (java.util.Date) in.readObject();
                 if (date != null)
                     value = new java.sql.Timestamp(date.getTime());

                 _field.set(obj, value);
             } catch (Exception e) {
                 logDeserializeError(_field, obj, value, e);
             }
         }
     }

     static class SqlTimeFieldDeserializer extends FieldDeserializer {
         private final Field _field;

         SqlTimeFieldDeserializer(Field field) {
             _field = field;
         }

         @Override
         void deserialize(AbstractHessianInput in, Object obj)
                 throws IOException {
             java.sql.Time value = null;

             try {
                 java.util.Date date = (java.util.Date) in.readObject();
                 if (date != null) value = new java.sql.Time(date.getTime());

                 _field.set(obj, value);
             } catch (Exception e) {
                 logDeserializeError(_field, obj, value, e);
             }
         }
     }

     /**
      * @see java.lang.Boolean#TYPE
      * @see java.lang.Character#TYPE
      * @see java.lang.Byte#TYPE
      * @see java.lang.Short#TYPE
      * @see java.lang.Integer#TYPE
      * @see java.lang.Long#TYPE
      * @see java.lang.Float#TYPE
      * @see java.lang.Double#TYPE
      * @see java.lang.Void#TYPE
      */
     private static boolean isPrimitive(Type type) {
         try {
             if (type != null) {
                 if (type instanceof Class<?>) {
                     Class<?> clazz = (Class<?>) type;
                     return clazz.isPrimitive()
                             || PRIMITIVE_TYPE.containsKey(clazz.getName());
                 }
             }
         } catch (Exception e) {
             // ignore exception
         }
         return false;
     }

     static final Map<String, Boolean> PRIMITIVE_TYPE = new HashMap<String, Boolean>() {
         {
             put(Boolean.class.getName(), true);
             put(Character.class.getName(), true);
             put(Byte.class.getName(), true);
             put(Short.class.getName(), true);
             put(Integer.class.getName(), true);
             put(Long.class.getName(), true);
             put(Float.class.getName(), true);
             put(Double.class.getName(), true);
             put(Void.class.getName(), true);
         }
     };
 }
	/*
	* Copyright (c) 2001-2008 Caucho Technology, Inc. All rights reserved.
	*
	* The Apache Software License, Version 1.1
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	*
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	*
	* 3. The end-user documentation included with the redistribution, if
	* any, must include the following acknowlegement:
	* "This product includes software developed by the
	* Caucho Technology (http://www.caucho.com/)."
	* Alternately, this acknowlegement may appear in the software itself,
	* if and wherever such third-party acknowlegements normally appear.
	*
	* 4. The names "Burlap", "Resin", and "Caucho" must not be used to
	* endorse or promote products derived from this software without prior
	* written permission. For written permission, please contact
	* info@caucho.com.
	*
	* 5. Products derived from this software may not be called "Resin"
	* nor may "Resin" appear in their names without prior written
	* permission of Caucho Technology.
	*
	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	* DISCLAIMED. IN NO EVENT SHALL CAUCHO TECHNOLOGY OR ITS CONTRIBUTORS
	* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
	* OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
	* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
	* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
	* IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*
	* @author Scott Ferguson
	*/

	package com.alibaba.com.caucho.hessian.io;

	import java.io.IOException;
	import java.lang.reflect.Constructor;
	import java.lang.reflect.Field;
	import java.lang.reflect.InvocationTargetException;
	import java.lang.reflect.Method;
	import java.lang.reflect.Modifier;
	import java.lang.reflect.ParameterizedType;
	import java.lang.reflect.Type;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.logging.Logger;

	/**
	* Serializing an object for known object types.
	*/
	public class JavaDeserializer extends AbstractMapDeserializer {
	private static final Logger log
	= Logger.getLogger(JavaDeserializer.class.getName());

	private Class _type;
	private HashMap _fieldMap;
	private Method _readResolve;
	private Constructor _constructor;
	private Object[] _constructorArgs;

	public JavaDeserializer(Class cl) {
	_type = cl;
	_fieldMap = getFieldMap(cl);

	_readResolve = getReadResolve(cl);

	if (_readResolve != null) {
	_readResolve.setAccessible(true);
	}

	Constructor[] constructors = cl.getDeclaredConstructors();
	long bestCost = Long.MAX_VALUE;

	for (int i = 0; i < constructors.length; i++) {
	Class[] param = constructors[i].getParameterTypes();
	long cost = 0;

	for (int j = 0; j < param.length; j++) {
	cost = 4 * cost;

	if (Object.class.equals(param[j]))
	cost += 1;
	else if (String.class.equals(param[j]))
	cost += 2;
	else if (int.class.equals(param[j]))
	cost += 3;
	else if (long.class.equals(param[j]))
	cost += 4;
	else if (param[j].isPrimitive())
	cost += 5;
	else
	cost += 6;
	}

	if (cost < 0 \|\| cost > (1 << 48))
	cost = 1 << 48;

	cost += (long) param.length << 48;

	if (cost < bestCost) {
	_constructor = constructors[i];
	bestCost = cost;
	}
	}

	if (_constructor != null) {
	_constructor.setAccessible(true);
	Class[] params = _constructor.getParameterTypes();
	_constructorArgs = new Object[params.length];
	for (int i = 0; i < params.length; i++) {
	_constructorArgs[i] = getParamArg(params[i]);
	}
	}
	}

	/**
	* Creates a map of the classes fields.
	*/
	protected static Object getParamArg(Class cl) {
	if (!cl.isPrimitive())
	return null;
	else if (boolean.class.equals(cl))
	return Boolean.FALSE;
	else if (byte.class.equals(cl))
	return new Byte((byte) 0);
	else if (short.class.equals(cl))
	return new Short((short) 0);
	else if (char.class.equals(cl))
	return new Character((char) 0);
	else if (int.class.equals(cl))
	return Integer.valueOf(0);
	else if (long.class.equals(cl))
	return Long.valueOf(0);
	else if (float.class.equals(cl))
	return Float.valueOf(0);
	else if (double.class.equals(cl))
	return Double.valueOf(0);
	else
	throw new UnsupportedOperationException();
	}

	static void logDeserializeError(Field field, Object obj, Object value,
	Throwable e)
	throws IOException {
	String fieldName = (field.getDeclaringClass().getName()
	+ "." + field.getName());

	if (e instanceof HessianFieldException)
	throw (HessianFieldException) e;
	else if (e instanceof IOException)
	throw new HessianFieldException(fieldName + ": " + e.getMessage(), e);

	if (value != null)
	throw new HessianFieldException(fieldName + ": " + value.getClass().getName() + " (" + value + ")"
	+ " cannot be assigned to '" + field.getType().getName() + "'", e);
	else
	throw new HessianFieldException(fieldName + ": " + field.getType().getName() + " cannot be assigned from null", e);
	}

	@Override
	public Class getType() {
	return _type;
	}

	@Override
	public Object readMap(AbstractHessianInput in)
	throws IOException {
	try {
	Object obj = instantiate();

	return readMap(in, obj);
	} catch (IOException e) {
	throw e;
	} catch (RuntimeException e) {
	throw e;
	} catch (Exception e) {
	throw new IOExceptionWrapper(_type.getName() + ":" + e.getMessage(), e);
	}
	}

	@Override
	public Object readObject(AbstractHessianInput in, String[] fieldNames)
	throws IOException {
	try {
	Object obj = instantiate();

	return readObject(in, obj, fieldNames);
	} catch (IOException e) {
	throw e;
	} catch (RuntimeException e) {
	throw e;
	} catch (Exception e) {
	throw new IOExceptionWrapper(_type.getName() + ":" + e.getMessage(), e);
	}
	}

	/**
	* Returns the readResolve method
	*/
	protected Method getReadResolve(Class cl) {
	for (; cl != null; cl = cl.getSuperclass()) {
	Method[] methods = cl.getDeclaredMethods();

	for (int i = 0; i < methods.length; i++) {
	Method method = methods[i];

	if (method.getName().equals("readResolve") &&
	method.getParameterTypes().length == 0)
	return method;
	}
	}

	return null;
	}

	public Object readMap(AbstractHessianInput in, Object obj)
	throws IOException {
	try {
	int ref = in.addRef(obj);

	while (!in.isEnd()) {
	Object key = in.readObject();

	FieldDeserializer deser = (FieldDeserializer) _fieldMap.get(key);

	if (deser != null)
	deser.deserialize(in, obj);
	else
	in.readObject();
	}

	in.readMapEnd();

	Object resolve = resolve(obj);

	if (obj != resolve)
	in.setRef(ref, resolve);

	return resolve;
	} catch (IOException e) {
	throw e;
	} catch (Exception e) {
	throw new IOExceptionWrapper(e);
	}
	}

	public Object readObject(AbstractHessianInput in,
	Object obj,
	String[] fieldNames)
	throws IOException {
	try {
	int ref = in.addRef(obj);

	for (int i = 0; i < fieldNames.length; i++) {
	String name = fieldNames[i];

	FieldDeserializer deser = (FieldDeserializer) _fieldMap.get(name);

	if (deser != null)
	deser.deserialize(in, obj);
	else
	in.readObject();
	}

	Object resolve = resolve(obj);

	if (obj != resolve)
	in.setRef(ref, resolve);

	return resolve;
	} catch (IOException e) {
	throw e;
	} catch (Exception e) {
	throw new IOExceptionWrapper(obj.getClass().getName() + ":" + e, e);
	}
	}

	private Object resolve(Object obj)
	throws Exception {
	// if there's a readResolve method, call it
	try {
	if (_readResolve != null)
	return _readResolve.invoke(obj, new Object[0]);
	} catch (InvocationTargetException e) {
	if (e.getTargetException() != null)
	throw e;
	}

	return obj;
	}

	protected Object instantiate()
	throws Exception {
	try {
	if (_constructor != null)
	return _constructor.newInstance(_constructorArgs);
	else
	return _type.newInstance();
	} catch (Exception e) {
	throw new HessianProtocolException("'" + _type.getName() + "' could not be instantiated", e);
	}
	}

	/**
	* Creates a map of the classes fields.
	*/
	protected HashMap getFieldMap(Class cl) {
	HashMap fieldMap = new HashMap();

	for (; cl != null; cl = cl.getSuperclass()) {
	Field[] fields = cl.getDeclaredFields();
	for (int i = 0; i < fields.length; i++) {
	Field field = fields[i];

	if (Modifier.isTransient(field.getModifiers())
	\|\| Modifier.isStatic(field.getModifiers()))
	continue;
	else if (fieldMap.get(field.getName()) != null)
	continue;

	// XXX: could parameterize the handler to only deal with public
	try {
	field.setAccessible(true);
	} catch (Throwable e) {
	e.printStackTrace();
	}

	Class type = field.getType();
	FieldDeserializer deser;

	if (String.class.equals(type))
	deser = new StringFieldDeserializer(field);
	else if (byte.class.equals(type)) {
	deser = new ByteFieldDeserializer(field);
	} else if (short.class.equals(type)) {
	deser = new ShortFieldDeserializer(field);
	} else if (int.class.equals(type)) {
	deser = new IntFieldDeserializer(field);
	} else if (long.class.equals(type)) {
	deser = new LongFieldDeserializer(field);
	} else if (float.class.equals(type)) {
	deser = new FloatFieldDeserializer(field);
	} else if (double.class.equals(type)) {
	deser = new DoubleFieldDeserializer(field);
	} else if (boolean.class.equals(type)) {
	deser = new BooleanFieldDeserializer(field);
	} else if (java.sql.Date.class.equals(type)) {
	deser = new SqlDateFieldDeserializer(field);
	} else if (java.sql.Timestamp.class.equals(type)) {
	deser = new SqlTimestampFieldDeserializer(field);
	} else if (java.sql.Time.class.equals(type)) {
	deser = new SqlTimeFieldDeserializer(field);
	}
	// support generic type of map
	else if (Map.class.equals(type)
	&& field.getGenericType() != field.getType()) {
	deser = new ObjectMapFieldDeserializer(field);
	} else if (List.class.equals(type)
	&& field.getGenericType() != field.getType()) {
	deser = new ObjectListFieldDeserializer(field);
	} else {
	deser = new ObjectFieldDeserializer(field);
	}

	fieldMap.put(field.getName(), deser);
	}
	}

	return fieldMap;
	}

	abstract static class FieldDeserializer {
	abstract void deserialize(AbstractHessianInput in, Object obj)
	throws IOException;
	}

	static class ObjectFieldDeserializer extends FieldDeserializer {
	private final Field _field;

	ObjectFieldDeserializer(Field field) {
	_field = field;
	}

	@Override
	void deserialize(AbstractHessianInput in, Object obj)
	throws IOException {
	Object value = null;

	try {
	value = in.readObject(_field.getType());

	_field.set(obj, value);
	} catch (Exception e) {
	logDeserializeError(_field, obj, value, e);
	}
	}
	}

	static class BooleanFieldDeserializer extends FieldDeserializer {
	private final Field _field;

	BooleanFieldDeserializer(Field field) {
	_field = field;
	}

	@Override
	void deserialize(AbstractHessianInput in, Object obj)
	throws IOException {
	boolean value = false;

	try {
	value = in.readBoolean();

	_field.setBoolean(obj, value);
	} catch (Exception e) {
	logDeserializeError(_field, obj, value, e);
	}
	}
	}

	static class ByteFieldDeserializer extends FieldDeserializer {
	private final Field _field;

	ByteFieldDeserializer(Field field) {
	_field = field;
	}

	@Override
	void deserialize(AbstractHessianInput in, Object obj)
	throws IOException {
	int value = 0;

	try {
	value = in.readInt();

	_field.setByte(obj, (byte) value);
	} catch (Exception e) {
	logDeserializeError(_field, obj, value, e);
	}
	}
	}

	static class ShortFieldDeserializer extends FieldDeserializer {
	private final Field _field;

	ShortFieldDeserializer(Field field) {
	_field = field;
	}

	@Override
	void deserialize(AbstractHessianInput in, Object obj)
	throws IOException {
	int value = 0;

	try {
	value = in.readInt();

	_field.setShort(obj, (short) value);
	} catch (Exception e) {
	logDeserializeError(_field, obj, value, e);
	}
	}
	}

	static class ObjectMapFieldDeserializer extends FieldDeserializer {
	private final Field _field;

	ObjectMapFieldDeserializer(Field field) {
	_field = field;
	}

	@Override
	void deserialize(AbstractHessianInput in, Object obj)
	throws IOException {
	Object value = null;

	try {

	Type[] types = ((ParameterizedType) _field.getGenericType()).getActualTypeArguments();
	value = in.readObject(_field.getType(),
	isPrimitive(types[0]) ? (Class<?>) types[0] : null,
	isPrimitive(types[1]) ? (Class<?>) types[1] : null
	);

	_field.set(obj, value);
	} catch (Exception e) {
	logDeserializeError(_field, obj, value, e);
	}
	}
	}

	static class ObjectListFieldDeserializer extends FieldDeserializer {
	private final Field _field;

	ObjectListFieldDeserializer(Field field) {
	_field = field;
	}

	@Override
	void deserialize(AbstractHessianInput in, Object obj)
	throws IOException {
	Object value = null;

	try {

	Type[] types = ((ParameterizedType) _field.getGenericType()).getActualTypeArguments();
	value = in.readObject(_field.getType(),
	isPrimitive(types[0]) ? (Class<?>) types[0] : null
	);

	_field.set(obj, value);
	} catch (Exception e) {
	logDeserializeError(_field, obj, value, e);
	}
	}
	}

	static class IntFieldDeserializer extends FieldDeserializer {
	private final Field _field;

	IntFieldDeserializer(Field field) {
	_field = field;
	}

	@Override
	void deserialize(AbstractHessianInput in, Object obj)
	throws IOException {
	int value = 0;

	try {
	value = in.readInt();

	_field.setInt(obj, value);
	} catch (Exception e) {
	logDeserializeError(_field, obj, value, e);
	}
	}
	}

	static class LongFieldDeserializer extends FieldDeserializer {
	private final Field _field;

	LongFieldDeserializer(Field field) {
	_field = field;
	}

	@Override
	void deserialize(AbstractHessianInput in, Object obj)
	throws IOException {
	long value = 0;

	try {
	value = in.readLong();

	_field.setLong(obj, value);
	} catch (Exception e) {
	logDeserializeError(_field, obj, value, e);
	}
	}
	}

	static class FloatFieldDeserializer extends FieldDeserializer {
	private final Field _field;

	FloatFieldDeserializer(Field field) {
	_field = field;
	}

	@Override
	void deserialize(AbstractHessianInput in, Object obj)
	throws IOException {
	double value = 0;

	try {
	value = in.readDouble();

	_field.setFloat(obj, (float) value);
	} catch (Exception e) {
	logDeserializeError(_field, obj, value, e);
	}
	}
	}

	static class DoubleFieldDeserializer extends FieldDeserializer {
	private final Field _field;

	DoubleFieldDeserializer(Field field) {
	_field = field;
	}

	@Override
	void deserialize(AbstractHessianInput in, Object obj)
	throws IOException {
	double value = 0;

	try {
	value = in.readDouble();

	_field.setDouble(obj, value);
	} catch (Exception e) {
	logDeserializeError(_field, obj, value, e);
	}
	}
	}

	static class StringFieldDeserializer extends FieldDeserializer {
	private final Field _field;

	StringFieldDeserializer(Field field) {
	_field = field;
	}

	@Override
	void deserialize(AbstractHessianInput in, Object obj)
	throws IOException {
	String value = null;

	try {
	value = in.readString();

	_field.set(obj, value);
	} catch (Exception e) {
	logDeserializeError(_field, obj, value, e);
	}
	}
	}

	static class SqlDateFieldDeserializer extends FieldDeserializer {
	private final Field _field;

	SqlDateFieldDeserializer(Field field) {
	_field = field;
	}

	@Override
	void deserialize(AbstractHessianInput in, Object obj)
	throws IOException {
	java.sql.Date value = null;

	try {
	java.util.Date date = (java.util.Date) in.readObject();
	if (date != null)
	value = new java.sql.Date(date.getTime());

	_field.set(obj, value);
	} catch (Exception e) {
	logDeserializeError(_field, obj, value, e);
	}
	}
	}

	static class SqlTimestampFieldDeserializer extends FieldDeserializer {
	private final Field _field;

	SqlTimestampFieldDeserializer(Field field) {
	_field = field;
	}

	@Override
	void deserialize(AbstractHessianInput in, Object obj)
	throws IOException {
	java.sql.Timestamp value = null;

	try {
	java.util.Date date = (java.util.Date) in.readObject();
	if (date != null)
	value = new java.sql.Timestamp(date.getTime());

	_field.set(obj, value);
	} catch (Exception e) {
	logDeserializeError(_field, obj, value, e);
	}
	}
	}

	static class SqlTimeFieldDeserializer extends FieldDeserializer {
	private final Field _field;

	SqlTimeFieldDeserializer(Field field) {
	_field = field;
	}

	@Override
	void deserialize(AbstractHessianInput in, Object obj)
	throws IOException {
	java.sql.Time value = null;

	try {
	java.util.Date date = (java.util.Date) in.readObject();
	if (date != null) value = new java.sql.Time(date.getTime());

	_field.set(obj, value);
	} catch (Exception e) {
	logDeserializeError(_field, obj, value, e);
	}
	}
	}

	/**
	* @see java.lang.Boolean#TYPE
	* @see java.lang.Character#TYPE
	* @see java.lang.Byte#TYPE
	* @see java.lang.Short#TYPE
	* @see java.lang.Integer#TYPE
	* @see java.lang.Long#TYPE
	* @see java.lang.Float#TYPE
	* @see java.lang.Double#TYPE
	* @see java.lang.Void#TYPE
	*/
	private static boolean isPrimitive(Type type) {
	try {
	if (type != null) {
	if (type instanceof Class<?>) {
	Class<?> clazz = (Class<?>) type;
	return clazz.isPrimitive()
	\|\| PRIMITIVE_TYPE.containsKey(clazz.getName());
	}
	}
	} catch (Exception e) {
	// ignore exception
	}
	return false;
	}

	static final Map<String, Boolean> PRIMITIVE_TYPE = new HashMap<String, Boolean>() {
	{
	put(Boolean.class.getName(), true);
	put(Character.class.getName(), true);
	put(Byte.class.getName(), true);
	put(Short.class.getName(), true);
	put(Integer.class.getName(), true);
	put(Long.class.getName(), true);
	put(Float.class.getName(), true);
	put(Double.class.getName(), true);
	put(Void.class.getName(), true);
	}
	};
	}